1. Field of the Disclosure
The present disclosure relates to a coupling device for a circuit breaker, and particularly, to a coupling device for a circuit breaker, which is provided between an outer handle assembly and an inner handle mechanism.
2. Background of the Disclosure
Generally, a circuit breaker is an apparatus capable of breaking an electric circuit in order to protect the electric circuit, when an overload or a short circuit has occurred. The circuit breaker has a function to switch on/off a load in order to connect/disconnect an electric circuit, when an abnormal current such as an overload and a short circuit has occurred. Switching on/off a load is performed by a mechanical operation.
A circuit breaker body is installed at an inner space of a distribution board. An outer handle assembly, which includes an outer handle and which is configured to control an on/off operation of the circuit breaker body, is installed outside the distribution board.
The outer handle assembly is a device installed at a distribution board panel, and manipulated by a user from outside so as to control the circuit breaker.
The outer handle assembly allows an operation of the circuit breaker to be smoothly transmitted to outside of the distribution board panel. On the contrary, the outer handle assembly allows a force applied from outside, to be smoothly transmitted to the circuit breaker.
FIG. 1 is a disassembled perspective view of a circuit breaker and an outer handle assembly in accordance with the conventional art, FIG. 2 is a longitudinal sectional view illustrating a connection part of the circuit breaker and the outer handle assembly of FIG. 1, and FIG. 3 is a longitudinal sectional view illustrating an assembled state of the circuit breaker and the outer handle assembly of FIG. 2.
Referring to FIG. 1, the conventional circuit breaker includes a circuit breaker body 1 installed in a distribution board; an inner handle 2 rotatably installed at the circuit breaker body 1, and configured to manipulate the circuit breaker; and an outer handle assembly 10 installed at a distribution board panel 5 so as to manipulate the inner handle 2, and connected to the inner handle 2.
The outer handle assembly 10 includes a cover 11 installed at the distribution board panel 5; an outer handle 12 rotatably installed at the cover 11, and manipulated by a user from outside of the distribution board panel 5; and a shaft 13 connected to the outer handle 12, and configured to transmit an operation of the outer handle 12 to the inner handle 2.
A coupling assembly 20, configured to transmit a rotational force of the outer handle assembly 10 to the inner handle 2, is coupled between the outer handle assembly 10 and the inner handle 2.
The coupling assembly 20 includes a first coupler 21 coupled to the shaft 13; a second coupler 22 coupled to the inner handle 2; a coupling spring 23 disposed between the first coupler 21 and the second coupler 22, and configured to allow the first coupler 21 and the second coupler 22 to be positioned on the same shaft; and a coupling bolt 24 configured to couple the first coupler 21 and the second coupler 22 to each other.
A key portion 21a is formed at a center of one side surface of the first coupler 21. A key groove portion 22a, configured to insert the key portion 21a of the first coupler 21 and configured to transmit a rotational force applied to the first coupler 21 through the shaft 13 to the second coupler 22, is formed at a center of one side surface of the second coupler 22 in correspondence to the key portion 21a of the first coupler 21.
If a user rotates the outer handle 12 in a state where the circuit breaker and the outer handle assembly 10 have been assembled to each other, a rotational force of the outer handle 12 is transmitted to the shaft 13 and the first coupler 21. Then the rotational force is transmitted to the inner handle 2 by the key portion 21a of the first coupler 21 and the key groove portion 22a of the second coupler 22, thereby being used to turn on/off the circuit breaker.
However, the conventional circuit breaker may have the following problems.
Considering an assembly tolerance which may occur between the outer handle assembly 10 and the inner handle 2, it is required to have a gap between the key portion 21a of the first coupler 21 and the key groove portion 22a of the second coupler 22. However, in a case where the outer handle assembly 10 is not concentric with the inner handle 2, the first coupler 21 and the second coupler 22 of the coupling assembly 10 are not concentric with each other as shown in FIG. 3. This may cause the key portion 21 to be partially detached from the key groove portion 22a. As a result, a rotational force of the outer handle assembly 10 may not be precisely transmitted to the inner handle 2. This may lower reliability of the circuit breaker.